Conveying of materials



Dec. 31, 1946., w E 2,413,479

CONVEYING OF MATERIALS Original Filed Dec. 7, 1939 6 Sheets-Sheet 1 Edwin LW'mganqi Asr To RN LYS Dec. 31, 1946.

CONVEYING Original Filed Dec. 7, 1939 am Compressor E. L. WIEGAND Y'Lg. 5.

OF MATERIALS 6 Sheets-Sheet 2 1wmL m am INVLNTO BY/ MM JM AI TORN EYS Dec. 31, 1946-. L, W IEGAND 2,413,479

' CONVEYING 0 MATERIALS Original Filed Dec. 7, 1939 6 Sheets-Sheet 3 Dec. 31, 1946.

E. L. WIE GAND CONVEYING OF MATERIALS Original Filed Dec 7, 1939 6 Sheets-Sheet 4 compags BLowoFF m Edwin L.Wuzgand INve 1- Exa Dec. 31, 1946. E. L. WIEGAND 2,413,479

CONVEYING OF MATERIALS Original Filed Dec. 7, 1939 6 Sheets-Sheet 5 y 1 w v ll iii I INvENToK W W 14M,-

ATTORNEYS i aaem waaaaa\w 51% 351 Pug ii.

LdWiLLLJ/V mgancl Dec. 31, 1946. EL. WIEGAND CONVEYING OF MATERIALS Original Filed Dec. 7, 1939 6 Sheets-Sheet 6 L .Wiagond IN v 1-: NTO K -r/ Mm?! ATTo uFJ s Patented Dec. 31, 1946 CONVEYING OF MATERIALS- Edwin L. Wiegand, Pittsburgh, Pa., assignor to Orefraction Incorporated, Pittsburgh, Pa., a corporation of Pennsylvania Original application December 7, 1939, Serial No. 308,002. Divided and this application August 28, 1944, Serial No. 551,561

7 Claims.

This application is a division of my application 308,002, filed December 7, 1939, now Patent 2,375,- 057, and relates particularly to conveying of material, includin by fluid pressure, and the principal object of the present invention is the improvement of apparatus for that purpose.

In the drawings accompanying this specification and forming a part of this application, there is shown, for purposes of illustration, one embodiment of apparatus embodying the invention, and in these drawings:

Figure 1 is a more or less diagrammatic view of the relation between material conveying means, grinding means, and separating means, as these means may be utilized in one embodiment of my invention,

Figure 2 is a sectional view of a material hopper and control device,

Figure 3 is a more or less diagrammatic view, particularly showing the fluid connections between parts of the apparatus,

Figure 4 is an enlarged sectional view of the solids metering and hoist tank, parts being shown in elevation, and parts being broken away, this View showing a solids inlet valve for the tank in open position,

Figure 5 is a fragmentary detail view showing the solids inlet valve in closed position,

Figure 6 is a section taken on the line 66 of Figure 5, looking in the direction of the arrows,

Figure 7 is an elevational view showing the relationship between an air strainer tank and upper and lower material feed tanks, and showing also valves in the connections in a certain position,

Figure 8 is a'view similar to Figure 7, omitting the air strainer tank and certain other parts, and showing the valves in full lines in a difierent position, and in dotted lines in still another position, and including the means for actuating the valves,

Figure 9 is a section taken on the line 9-9 of Figure 8,

Figure 10 is an enlarged fragmentary sectional view through the upper and lower material feed tanks,

Figure 11 is an enlarged sectional view through one of the valves shown in Figure 10,

Figure 12 is a sectional view correspondin generally to the line [2-42 of Figure 11, parts being shown in elevation, and

Figure 13 is an electrical diagram, showing the electrical connections between parts comprised in the apparatus.

Referring to the schematic arrangement shown in Figure l, the embodiment of the invention there illustrated comprises a container 55 adapted to contain material to be ground, and hereafter referred to as the new-materials container. The new-materials container 50 may be formed with an outlet spout 5| discharging into a funnel 52 carried by the receiving end 53 of an elevating device 54, such as the bucket elevator here shown. A suitable slide valve 55 is interposed in the outlet spout 5! to regulate the flow of material from the new-materials container 50 to the receiving end 53 of the elevator 54. The elevator 54 may be driven by means of an electric motor 55, and may also have a signal device, such as the electric light 57, to indicate when the elevator 54 i operating. The discharge end 58 of the elevator 54 discharges into a conduit 59 leading to a blending and metering hopper 50, desirably provided with an inclined false bottom Ella, and having high and low limit controls 6! and 62, so as to control operation of the motor 56 of the elevator 54, the connections being such that the motor 55 of the elevator 54 is automatically started when the level of the material falls below the low level device 62, and the motor 55 is automatically stopped when the material rises up to the high level device 6 I.

Preferably, the high level control 6| comprises a rotatable housing disposed at the outside of the hopper, the housing containing a mercury switch which is electrically connected to the motor 55, the housing being rotatable in one direction by a vane Bla within the hopper 5!! (see Figure 2). The low level device 52 comprises a pivoted vane 62a, within the hopper 60, urged counterclockwise, as viewed in Figure 2, by a counterweight 62b. The vanes 5 la and 62a are shown in Figure 2 in the position they occupy when the hopper 50 is full of material, as indicated by the upper dotted mount line M, the vane Eta standing about 45 counterclockwise to the right of the vertical and the vane 62a about 45 clockwise to the left of the vertical. The vanes 6 la and 62a are shown as connected by a lost motion connection which includes a rod 620 disposed at the outside of the hopper 60, pivoted at its lower end to a crank 62d movable in unison with the vane 62a, and having at its upper end a slot with which cooperates a pin on a crank 62c movable in unison with the vane 6 la.

Withdrawal of the material from the hopper 65 causes the surface of the mound of material to fall, but for the time being the vane Bia, by friction adjustment of its shaft, remains in the position shown in Figure 2, even though the surface of the mound adjacent the vane fila recedes away 3 from that vane. When the mound of material decreases in height so that its surface adjacent the vane 62a recedes sufficiently away from that vane, the counterweight 82b causes counterclockwise rotation of the vane to a position about 45 counterclockwise to the right of the vertical, such movement being transmitted through the lost motion connection so as to move the vane 6 la clockwise to a position about 45 to the left of the vertical, thus moving the mercury switch to 'its' on position, in which position it completes the circuit through the motor 55, whereby material is delivered to the hopper Si! by the elevator 56.

When the mound of material in the hopper increases, either by reason of delivery by the elevator 54 or otherwise, as will appear hereinafter, the material acts against the vane 62a and eventually moves the vane 62a clockwise, into the position shown in Figure 2, against the urging action of the counterweight, when the mound reaches the height indicated by the lower dotted mound line m. However, such movement of the vane 62a will not affect the vane Ella because of the lost motion connection therebetween. When the mound of material rises enough, the material will act against the vane 65a and eventually move it counterclockwise to the-position shown in Figure 2, when the mound has increased to the upper dotted mound line M, thereby causing rotation of the mercury switch to its position, and thus interrupting the circuit of the motor 58.

Positioned alongside of the hopper 60 is a second elevator 63, having its inlet end 54 receiving material from the lower end of the hopper Ell, as by means of a conduit 85, a suitable slide valve 66 being so interposed as to control the amount of material flowing from the hopper 6! The elevator 53 is driven by an electric motor 61, and may have a signaling device, such as the electric light E3, to indicate when the motor 6? is running. The discharge end 63 of the elevator 63 leads to the inlet of a solids valve Hi the outlet of which communicates with the interior of a charge metering and hoist tank ll. The hoist tank H has high and low level devices 12 and 73 respectively, so related to other parts (as will more fully appear) as normally to cause the motor 6? to operate when the material is below the low level device 53, and to interrupt the circuit of the motor 6'! when the material reaches the high level device i2.

A fluid under pressure, in the present instance, air, may be admitted to the hoist tank TH through a conduit i4, and such air may be released from the hoist tank H through either the conduit i l or a blow-off conduit l5. With material in the hoist tank 1!, and air under pressure supplied to the hoist tank l'l through the air conduit 1%, the material in the hoist tank H is forced to move through a conduit 16 to a connection conduit ll" between an air strainer tank "i8 and an upper material feed tank 19, a valve 89 being interposed in the connection conduit TI to permit admission of material to the upper tank i and to enable the tank to be placed under fluid pressure. Assuming the valve 80 to be in open position, the material which passes through the conduit '16 is delivered to the connection conduit H, the air used for hoisting purposes being strained by and vented from the strainer tank 18, and the material dropping into the upper feed tank 19.

The upper feed tank is is connected to a lower feed tank 8| by means of a connection conduit 82, a valve 83 being interposed in the connection 4 conduit 82 to permit transfer of material from the upper tank 19 to the lower tank 8!, and to enable the lower tank to be maintained under pressure. The lower tank 8! has an outlet conduit 86, a valve 85 being interposed in the outlet conduit iii for permitting or interrupting the outflow of material from the lower tank 8!. Means, shown in Figure 3, is provided for admitting air under pressure to the upper and lower tanks 19 and Bi, as will more fully appear.

Assuming that the valve 83 is closed and the valve 85 is open, and assuming also that material is in the lower tank 8 l, and that this tank is under air pressure, the material from the tank 8! will be forced through the outlet conduit 8-4, and through a hose conduit 86 to the breech 8! of a gun 88, and through this gun 88 to the grinder case 89, the ground material passing through a conduit 98 to a first separating device 9! of the cyclone type, The heavier material in the first separating device 9i may gravitate past a check valve 92 used to build up a head of material at the discharge end of the first separating tank 9!, through a conduit 93 to a funnel 94, and from the funnel 94 to a screen chamber 95 of a screening device 96. The screening device 95 may be of the vibrating type, having a screen 97 over which the material is shucked, the screen having a certain predetermined mesh size, as for example 200 mesh.

The material which passes through the screen 9'1 falls into a hopper 93, the outlet of the hopper 93 having a bagging device 99, to which a bag I99 is attached, the bag I receiving such material for shipment if desired. For convenience, the bag 19%] may be disposed on a platform ml of a scale Hi2, so that the amount of material delivered to the bag Hi0 may be weighed as it is delivered to the bag. That material which does not pass through the screen 9"! is discharged from the screen chamber through a conduit 13, and back to the mixing hopper 65]. Additional material, from the new materials container 56, may be added to the hopper Si! by means of the elevator 5 3, the high level device GI limiting the amount of new material delivered to the hopper B9. In this manner the material removed from the system is automatically replaced with new material from the new materials container 53. The slide valve 55 may be adjusted to a particular fiow rate, such rate being determined by'the rate at which finished material is removed from the system.

Additional separating means ,is provided for additionally separating that material which does not gravitate from the first separating device 9!, and this means comprises, among other parts, a pump, in this instance a blower fan ltd, disposed within a fan chamber Iii-5 and driven by an electric motor I06. The outlet of the fan chamber #35 is branched, one branch NH leading to the atmosphere, and the other branch I88 bein connected to one end of a conduit I09, the opposite end ll!) of the conduit I09 leading tangentially into the first separating device 53!, if desired in two diametrically disposed tangential branches Hlla and Hill). Slide valves H! and H2 are respectively interposed in the branch conduits l0! andlilB, these valves being independently adjustable so' as to regulate the amount of air discharged by the blower through the respective branch, for a purpose to appear.

The upper discharge outlet of the separating device 9| is connected to the inlet of the blower chamber 565, and in this instance certain devices -ber I85.

are interposed in this connection. Extending from the upper discharge outlet of the first separating device 9| isa separating column, H3, of any suitable cross-sectional form, area, and length, which extends vertically and is connected to a conduit H4 which is tangentially connected to the upper end of a second air separating device H6. Desirably the separating column II 3 is enlarged with respect to the conduit H4, and may taper toward its lower end to cause hindered settling. The device H6 may be of the cyclone type, comprising a chamber having an upper cylindrical portion In and a downwardly tapering conical portion IIB. A bagging device H9 is connected to the lower end of the conical portion H8, and has attached thereto a bag I29 for receiving material gravitating downwardly of the conical'portion H8. The upper end of the second separating device H5 is formed with a housing I2I communicating with the interior of the device H6. The housing I2I communicates by means of a conduit I22 with a dust collector or separator I23, which may be of any suitable type. The lower end of the dust separator I23 has attached thereto a bagging device I25, and the air outlet of the dust'separator I23 is connected bya conduit I25 to the inlet of the fan chamber I85.

Assuming that the motor Idiiis operating, and that the valve H I is at least partially open, and that ground material, along with air used in grinding it, is being delivered through the conduit 98 to the first separating device ill, the material which under the air conditions prevailing in the separating system is not heavy enough to gravitate at once from the separating device M, will be picked up by the stream of air in the column H3. Some of this material will continue to be carried by that stream to the top of the column H3 and through the conduit H4 to the upper end of the second separating device H8, and will be caused to swirl in this upper end because of the tangential connection of the conduit H4. The heavier materials in the second separating device H6 will gravitate downwardly through the conical portion H8, and will be delivered to the bag I28 through the bagging device H9. The lighter material will be carried upwardly by the air stream through the housing HI and the conduit I22, to the dust collector I23, where the dust will be separated from the air, the dust particles being discharged from the bottom of the dust separator I23 and to the bagging devivce I24, and the air passing to the conduit I25 and back to the inlet of the blower cham- Some of the material which enters the separating column H3 from the separating device 9I does not continue with the upwardly moving stream of air into the conduit Ihl, but gravitates back through the stream into the separating device 9I and finally reaches the lower or discharge end of the separating device 9|, and thus the separating action of the system is improved.

. Depending upon the setting of the slide valves I I I and I I2, either an under-pressure or an overpressure condition (With respect to atmospheric pressure) can be made to exist in the first separating device -9I. Usually the valve H2 is partially or completely closed, and the valve I I I partially or completely open, so that an under-pressure or partial vacuum exists within the first separating device 91 and in the column H3, whereby material readily passes from the grindor case 89 to the first separating device 9i, and

no back pressure is created in the conduit 98 leading from the grinder case 89. Also,; usually the valves III and I I2 are adjusted to effect substantially zero (atmospheric) pressure in the grinder case 89, thereby to avoid back pressure in the grinder case 89 that might interfere with the operation of the grinder gun. However, it will be apparent that the pressure conditions in the grinder case and in the separating system can be regulated by adjustment of the slide valves I i I and I I2 to obtain any desired pressure conditions. Furthermore, the velocity of the upwardly moving stream of air in the separating column H3 may be adjusted to a most suitable velocity so that the separating function of the column H3 will be optimum.

The first separating device 98 may be moved from the position shown in full lines in Figure 1 to the position shown in dotted lines, wherein its lower end no longer communicates with the conduit $3, but instead communicates with a conduit i35 leading to a tank Hi5, hereinafter referred to as a by-pass tank. The lower end of the tank I36 carries a bagging device I 3'6, to which a bag I38 may be attached, and a check valve lfid is interposed in the conduit I35. In this position of the device 9| the ground material, excepting only a controllable amount and size of very fine material, instead of going to the screen chamber 95, passes directly to the by-pass tank let. The conduit H3 in this position may still be connected to the conduit I M. The by-pass tank connection is particularly useful when it is desired to make an unscreened ground aggregate, with only a minimum of extreme fines removed.

The fluid pressure system is particularly shown in Figure 3, and in this embodiment uses air as the fluid, although any other suitable fluid may be used. The system comprises an air compressor I45, a conduit I46 leading from the air compressor M5 to an air storage tank Hi1, and a three way valve M8 interposed in the conduit M6, the valve H18 in one position establishing communication between the compressor M5 and the storage tank M7, and in another position establishing communication between the storage tank I81 and a tank Hi9, hereinafter referred to as the waste air tank, the latter tank having safety valves i578 adapted to open at a predetermined pressure, as for example to pounds per square inch.

To start the apparatus initially, the valve 38 is set to establish communication between the air compressor I45 and the storage tank I41, and any desired pressure is built up in the tank ME. The valve M8 is then turned to establish communication between the storage tank I41 and the waste air tank I49, and air is permitted to flow to the tank hi9 until the predetermined p s is built up in the tank I49. The valve I48 is then turned to its'third position, wherein it establishes communication between the waste air tank I 49 and a conduit I52, for a purpose hereinafter explained. A manual control valve I55 may also be interposed in the conduit I48 for controlling the fiow of air through the conduit I46, and a pressure indicator I56 may be connected to the conduit I46 ahead of the valve I55. Pressure indicators I55 and I56a may be connected to the waste air, tank I49 and to the storage tank It; respectively.

Leading from, the waste air tank I69 is a .conduit I59, a valve I68 being interposed in this conduit to permit or interrupt fiow of air therethrough, the valve I58 being actuated by means of a solenoid Hit. The conduit I59 leads to a manually operable valve I62, preferably of the three-way packed plugcock type, one outlet 163 of the valve E52 leading by means ofaconduit $64 to the inlet conduit id of the hoist tank II, and the other outlet U55 leading by means of the conduit I66 to a dust separator IN. The dust separator Ifil has an air outlet I68 leadingtc a mufiler ltd for the purpose of muflling the noise of the escaping air, the air pa'ssingfrom the muliler Iiit to the atmosphere.

The blow-off conduit I of the hoist tank H is connected to a conduit I10 through a valve III interposed to permit or interrupt the flow of air through the conduits I5 and Illfi, the-valve III being actuated by a solenoid I12. The conduit I!!! is connected with the conduit 185, and through the conduit I55 with a conduit H3 'which leads to one outlet I i l of a manually operable valve I35 which may be of the three-way type in all respects similar to the valve I62. Another outlet I'Ifi of the valve I is connected by means of the conduit iti o the three-way valve while the third outlet I18 is connected by means of a conduit H9 to the upper tank I9, a check valve I88 being interposed in the conduit I79 to permit air to flow only outwardly of the upper tank 18 and to prevent reverse flow.

The present embodiment provides a separate air compressor I8! for supplying air under pressure to the upper and lower tanks 79 and 8!, The compressor Isl is connected to a storage tank I82 by a suitable conduit as shown. Extending from the storage tank I82 to the lower tank 8! is a conduit 539 in which are interposed a line cock I83, a line gauge I8 1, a pressure regulator i35, a three-way meter by-pa'ss I86, another line gauge 58?, a stop cock I82, a stop cock Itfia to permit and interrupt the flow of air to the tank 8!, and a check valve I9! to permit air to flow only into the lower tank 8! and to prevent reverse flow. It will be apparent that the conduit I89 furnishes direct, regulated, and controllable pressure to the tank 8i, so that material within the tank will be positively forced out by this direct pressure through the conduit 86 and the gun 88.

A conduit W2 is tapped into the conduit I89 between the regulator i823 and the stop cock IBM, and has a check valve 593 interposed therein to permit air to pass only from the conduit I8 through the conduit E92 and to prevent air from passing from the conduit 92 back to the conduit I89. The conduit N92 is connected to one port I9 3 of a manually operable valve which may be of the three-way type similar to the valves I52 and H5, 3, second port let; of the valve I95 being connected by means of a conduit I 9'5 to the lower tank 85, a pressure indicating device i923 being connected to the conduit I532. The other port I53 of the valve I95 is connected by means of a conduit 2% to the upper tank is, and a pressure indicating device 22H may be connected to this conduit 2%.

Describing generally the pressure system, it will be assumed that material is in the hoist tank II, but that no material is in the upper and lower feed tanks I9 and ill, and it will also be assumed that the valve 88 in the upper tank is open, and that the valve 83 between the upper and lower tank I9 and Bi and the valve 85 below the lower tank 8I, are closed. The control lever of the valve It? is turned to the position marked Air input, hoist, soas to permit air under pressure from the waste air tank I49 to flow through the conduit I59, the valve i158 (assuming that this valve is open), the conduits ltdzand 14, to the hoist tank II, and after a predetermined amount of pressure has been built up within the hoist tank H, the material will be forced through the conduit 'IGto the connection conduit 71, and into the upper tank 19. The pressure required to move the material in the hoist tank II depends upon the characteristics of the material and the speedwat'which it is desired to move such material. 'The air used to move the material to the upper tank I9 is filtered by passage through the air strainer tank I8 and escapes therefrom. After all of the material has been hoisted t0 the upper tank I9, the operator may turn the control lever-of the valve I62 from the air input, hoist position to the blow-oil position, so that the pressure within the tank II may be relieved by air flow through the conduit I 54, the port I55 of the valve I62, the conduit I66, the dust separator tank I61, the muiii-er I69, and to atmosphere, or the pressure may be relieved otherwise as will appear hereinafter.

During operation of the apparatus, air under pressure is delivered directly to the lower tank 8I by means of the conduit I83. Assuming that the material in the lower tank is low, and that material already has been hoisted to the upper tank Iii in'a manner hereinbefore described, and that the valves 86, 83, and 85, are closed, the control lever of the three-way valve I is turned to compress position, and in this position of the valve I95 air from the conduit I52 passes through the valve H95 and through the conduit 28% to the upper tank 59, and air is thus admitted until the pressure indicator Zfil shows that the pressure in the upper tank i9 is substantially equal to that in the lower tank 8!. The control lever of the valve I95 is then moved to equalize position, whereupon the conduit E92 i shut oil, and communication between the tanks l9 and iii isestablished by means of the conduit I91, the valve. 95, and the conduit 2%, so as to insure that the pressure within the lower tank SI is not greater than that in the upper tank I9. Then the valve 83 is opened to permit the material from the tank I9 to pass to the tank 85. The control lever of the valve I95 may then be moved to dead position.

If desired, air under a pressure higher than that within the tanks 79 and Si may be introduced into the upper tank i9 so as to force the material from the tank i9 into the lower tank 8i. To provide for such higher pressure air, a threeway valve 283 may be interposed in the conduit 2%, one port 253! of the valve 2533 being connected to a conduit 2% tapped into the pressure line E39 ahead of the pressure regulator I93 to receive a higher pressure than exists in the part of the conduit I89 downstream of the regulator. The other ports 29% and Bill of the valve R23 are interposed in the conduit 2%. Thus with the valve2%3 inposition to establish communication between the conduit 2% and the part 252% of the conduit 288, and to cut off communication with the part idea of the conduit 206, the air under higher pressure in the upper tank I9 will surge to the lower tank 8i, and will forcibly rei move any remaining material from the tank is.

When all the material has been delivered to the lower tank at, the valve 83 is moved to closed position, and the valve 35 "isopenedthus feeding material to the sun 88. To release the pressure in the upper tank It, the control lever of the valve I15 is moved to v a position indicated by the letter a, in which position the air from the upper tank 19 is permitted to move through the conduit I19, the valve 115, the conduit I52, through the valve I48, and to the Waste air tank [49, the operator being notified when the maximum pressure in the waste air tank I49 has been reached, either by a single device, or by the blowing oif of the safety valves lll. At this point the operator may move the control lever of the valve I75 to the position indicated by the letter I), so that the remainder of the air under pressure from the upper tank 19 may fic-w through the conduit I19, the valve H5, the conduit 1'53, to the dust separator I61, through the mufiler I69, and to the atmosphere. After all the air under pressure has been removed from the upper tank 19, the control lever of the valve H5 may be returned to its dead position. The valve 89 may then be opened, and material may again be hoisted from the hoist tank H to the upper tank 19.

Referring to Figure 4, the hoist tank H comprises a cylindrical body Zlil having an integral dome-shaped top 2| I and a downwardly tapering bottom 2 l 2, the extremity of the bottom 212 being provided with a clean-out opening 2l3 which is closed by a plug 2M, and extending centrally of the tank H is an elongated preferably metallic tube 2 l 9 open at its lower end and screw-threaded at its upper end and received within a coupling 220 secured to the top 2!! of the tank 7!. The tube 2I9 is desirably provided with a rubber lin- The solids inlet valve m is carried by the top 2!! of the tank H, the top 2! l having an interiorly screw-threaded tube portion 223 secured thereto, as by welding, the tube portion 228 screw-threadedly receiving a tubular part 229 which in turn screw-threadedly receives a nipple 230 forming part of the valve casing, the construction being such that the axis of the valve 10 is at an angle to and intersects the axis of the elongated tube 2). The valve 19 has an inlet port 23! communicating with the discharge end 69 of the elevator 83, and also has a bearing 232 for a valve plunger 233. Pivoted to the lower end of the valve plunger 233 is a cap-form valve body 234 formed with an annular recess 235 arranged with a gasketed seat to close the inner extremity of the tube part 229 when the valve body is in closing position, as best seen in Figure 5.

The upper outer extremity of the valve plunger 233 is provided with a transversely disposed pin 23% engageable with the defining margins of slots 23! formed in respective arms 238 of a bifurcated operating lever 239, the lever being pivoted on a pin 240 carried by arms 2M extending from the casing of the valve Ill. The lever 239 is operable by a handle portion 2 12. Rotatable with the lever 239 is the casing 243 of a mercury switch. The casing of the valve 19 is also provided with a pair of ears 2M, carrying a pivot 245 for a swingable latching lever 2&6, the lever having an operating handle 24'! and also having a notch 248 for receiving a tooth or detent 2133 carried between the arms 238. As shown in Figure 5, with the valve 70 in closed position, the detent 249 fits into the notch 2A3 of the lever 246, and prevents opening movement of the valve 19. The valve 10 may be opened by manually engaging the operating handle 24'! and moving the latching lever 256 so as to disengage the detent 2 19, movement of the lever 239 causing the detent 249 to ride on the adjacent marginal surface of the lever 266.

Means may be provided for locking the latching lever 249, as a solenoid 250 having a core 25l adapted to fit slidably in apertures Zita and 23911 formed respectively in the latching lever 249 and the lever 239, the apertures being alined when the latching lever prevents movement of the lever 239, as shown in Figures 5 and 6. The solenoid core 25| is biased to the locking position, shown most clearly in Figure 6, as by a spring 25m, and the construction and arrangement is such that when the solenoid 259 is energized the core 25! will be drawn into the solenoid, against the bias of the spring 25m, thereby withdrawing the core 25! from the apertures 246a and 239a and releasing the levers 246 and 239 for desired manual movement.

Referring to Figure 4, it will be noted that when the valve plunger 233 is moved to open position, the valve-body 234 will engage the elongated tube 2%!) and cause the valve-body to pivot about the valve plunger 233 to its open position as shown.

The air inlet conduit l4, and the air blow-off conduit 15, may be suitably coupled to spuds secured to the top wall 2 to the tank H. The tube 2:19 is suitably connected to and in communication with the conduit It preferably of rubber or rubber lined, and if desired the conduit 76, or the rubber lining thereof, may be continuous with the lining of the tube H9.

The high level and low level responsive devices 12 and 13 respectively comprise housings 254 rigidly carried by the tank 1|, as by means of plugs 255 threaded into collars carried by the cylindrical portion 219 of the tank 1|. Rotatable within each of the plugs 255 is a shaft 256 carrying a vane 251, the vanes being each suitably biased to a generally horizontal position as shown by the vane on the high level indicating device 12, and being moved to a generally vertical position, as shown by the'vane of the low level device 13, by the material within the tank 1 I, movement of the shafts causing operation of switch means within the respective housings 255, as will more fully appear. As shown in Figure 4, the tank 1! also carries a pressure responsive device 258, responsive to pressure within the tank, and constructed and arranged to actuate a switch 259 connected thereto for a purpose to be set forth.

The connection conduit 11, as best shown in Figure 10, comprises stub portions 269 and 26!, respectively connected to the air strainer tank 18 and the upper tank 19, the stub portions 260 and 26!. being connected to oppositely disposed branches of a three-way fitting 262, the other branch of the fitting 292 having therein a bushing or gland 263 through which is disposed a tube 258 the outer end of which is coupled to the conduit i6 and the inner end of which is formed with a downwardly curved spout 269 directed toward the stub portion 26l of the conduit 11.

The air strainer tank 18 is supported from the connection conduit 11, as best shown in Figure 10, the portion 260 passing through and being suitably fastened to a bottom closure plate 210 for the tank [9. As can be seen in Figures 3 and '7, the strainer tank 18 has a top closure plate 211, and a conduit 2T9 establishes communication between the interior of the tank T8 and the interior of the dust separator [91. The lower open end of a dust bag 283, such as a dust bag ordinarily used on a vacuum cleaner, is suitably connected to communicate with the conduit portion 26!]. Means may be provided for shaking the bag 283 so that it may be kept in condition to filter and to permit the escape of the air used to hoist the material to the upper feed tank 19, and for that purpose the present embodiment comprises a 1 1 plunger 289 suitably passing through the top closure plate 211.

The stub portion 261 of the connection conduit 11 is screw-threadedly received within a tubular portion 291 (see Figure 10) forming part of the housing for the valve 30 associated with the upper feed tank 19. The upper tank 19 has its upper and lower portions 298 of conical form. The upper and lower ends of the tank '19 are open, and are surrounded by integral flanges 301 and 302 respectively. An annular flange 303 overlies the upper flange 301, a gasket 3114 being interposed between the flanges, and bolts 305 pass through apertures in the flange 303 and are received within screw-threaded apertures formed in the flange 301. The flange 3113 is formed with a central screw-threaded aperture for receiving the lower threaded end of the tube portion 291, and a valve-seat block 391 (see Figure 11) is fitted into the lower end of the tube portion 291, and desirably is welded to the tube portion 291, as shown at 398. Also the block 301 is formed with a valve seat 3139, and extends partially into the upper open end of the upper tank 19.

Extending transversely from the upper end of the tube portion 291 is a bearing tube 310, a web 31 1 reinforcing the connection between the bearing tube 313 and the tube portion 291, and journaled within the bearing tube 31 [1 is a valve operating shaft 312 having a squared outer end 313 for receiving one end 314 of a valve lever 315. The bearing tube 310 extends a slight distance within the tube portion 291, and the operating shaft 312 at this point is reduced in diameter and squared to fit into a squared opening formed in a crank 316, a set screw holding the crank 316 to the shaft 312. The crank 316 carries an off-center pin 311 (see Figures 11 and 12) fitting through a slot 318 formed in a flattened portion 321 of a rod 319, the pin 311 having a headed portion 320 holding the rod assembled on the pin 311. The rod 319 also has a portion 322 round in cross-section and slightly bent, as best shown in Figure 12, and the lower end of the rod 319 is formed with a conical enlarged portion 323 and with a reduced extremity 324 forming a shoulder 325 with the conical portion 323. A frusto-conical block 326, having a central aperture, is fitted on the reduced extremity 324, and a resilient valve body 321, preferably formed of rubber and having a generally frusto-conical outline, is fitted over the reduced extremity 324, and an inverted cup-shaped disk 328 is positioned to hold the valve member 321 in position, a nut 329 being screw-threaded on the end of the reduced extremity to hold the disk 328, the valve member 321, and the block 326, in position on the valve arm 319, the nut preferably being welded to the disk 328 as best shown in Figure 11.

The valve 33 is shown in closed position in Figures 10 through 12. Sufficient rotation of the shaft 312 in a direction to cause counter-clockwise movement of the crank 316, which reference to its position shown in Figure 12, will cause unseating f the valve body 321 from the valve seat 399. The slot 318 permits the valve body 321 to be pressed more firmly against the seat 309 by fluid pressure within the tank, and also permits the pin 311 to give a hammer blow to the lower end of the slot in opening the valve.

The bore of the bearing tube 310 may be enlarged so as to accommodate between it and the shaft 312 a tubular gland 319a forced against packing 331 by a gland nut 332 threaded on the outer end of the bearing tube 310. The enlarged part of the bore of the tube 310 extends to near the inner end of the tube 319 so that the packing 331 effectively prevents grit from getting between the journal surface of the shaft 312 and the cooperating bearing surface of the gland 3111a.

The lower feed tank 81 is formed in all respects similar to the upper tank 19, having upper and lower conical portions 339, and also upper and lower flanges 333 and 334 respectively.

Underlying the lower flange 392 of the upper tank 19 is an annular flange 335 (see Figure 10) having a central screw-threaded aperture, and overlying the upper flange 333 of the lower tank 81 1s an annular flange 336 also having a central screw-threaded aperture, and the connection conduit 82 between the upper tank 19 and the lower tank 81 comprises a tube portion 331 which extends between and has screw-threaded ends respectively received in the apertures formed in these flanges 335 and 336. The tube portion 331 forms part of the valve housing for the valve 83. Extending transversely from the upper end of the tube portion 331 is a bearing tube 338 in which is journaled a valve operating shaft 339 having a squared end 340 for receiving an intermediate portion 341 of a valve operating lever 342. The inner end of the valve shaft 339 is connected to a crank 343 in the same manner as the shaft 312 is connected to the crank 316. A rod 344, similar in all respects to the valve arm 319, is connected to the crank 343, and carries a resilient valve body 343 which cooperates with a valve-seat block 346, the parts 345 and 346 being similar to the parts 321 and 301 hereinbefore described. The valve shaft 339 may be packed in the same way as the shaft 312.

The air strainer tank 18, and the upper and lower feed tanks 19 and 81, may be at least in part carried by a frame structure 341, resting upon a suitable supporting surface. The upper and lower tanks 19 and 81 are further held rigidly connected by means of a plurality of connecting rods 350 (see Figure '1) extending between angle pieces 351 fastened to the respective tanks.

Referring particularly to Figures 7 and 8, the valves and 93 are adapted to be moved in a predetermined order by operating means 356. The valve lever 315 has a pin 351 spaced from the valve shaft 312, and the extremity of the valve lever 315 is provided with a weight 358 arranged to urge the valve lever arm 315 to its valve-closing position shown in Figure '1. A resilient stopper block 359, desirably formed of rubber, is carried by the upper tank 19 in position to limit movement of the weight 358. The valve lever 342 has a pin 36!] carried spaced from the valve shaft 339, the pin 360 being in longitudinal alinement with the pin 351 carried by the arm 315. The valve lever 342 carries a weight 361 arranged to urge the lever 342 to its valveclosing position shown in Figure 7, a resilient stopper block 362 being carried by the lower tank 81 in position to limit movement of the weight 361.

The operating means 356 further comprises a pair of longitudinally spaced-apart elongated metallic strips 363 and 364, the strips being adjustably connected by a turnbuckle arrangement 365. The strip 363 has an elongated slot 366 for receiving the pin 351 carried by the valve lever 315, while the strip 364 has an elongated slot 361 for receiving thepin 360 carried by the valve lever 342. A coil spring 368 has its 13 ends connected respectively to the pins 351 and 380, the spring 368 additionally urging the valve levers 3&5 and 342 to their valve-closing position shown in Figure '1.

Connected to the lower end of the strip 364 is an elongated rod 369 having its lower end pivotally connected to one arm 310 of a bell crank lever 31!. The lever 31! is pivoted at 312 to a. supporting frame 313 carried from a suitable supporting surface. Also carried by the supporting frame 313 is a quadrant 314. The other arm 315 of the bell crank lever 31f is positioned to traverse the quadrant-314 and includes an indicating portion 318 and an operating arm 311. The quadrant 31E is provided with three notches 318 located on the quadrant at the positions marked with the legends fill, compress, or blow-off, and dump. The operating arm 311 has a manually releasable spring-pressed detent engageable within any one of the notches 318, to hold the arm 311 in any one of the positions. The quadrant 31 also carries a solenoid 319 having a core 380 which is adapted to be 7 moved into the position shown in Figure 9 by a spring 388a when the solenoid is deenergized, so that when certain conditions exist, as will appear, the core will extend into the path of movement of the indicating device 318 to prevent the operating arm 311 from being moved to dump position.

With the operating lever 311 in the position shown in full lines in Figure 8, that is, in the fill position, the valve levers 315 and 3&2 are in the position shown in full lines in Figure 8,

and the valve 80 is open and the valve 83 is closed, thus permitting material to be delivered to the upper feed tank 18, while at the same time permitting the maintenance of an operating pressure within the lower tank 8|. It will be noted that the slots 388 and 381 respectively formed in the strips 363 and 364 are so proportioned that the weight 38! may maintain the valve 83 in its closed position, while the weight 358 is lifted to provide opening of the valve.

80. When the operating lever 311 is moved to the compress or blow-off position, the valve levers 3i5 and 342 are in. the position shown in Figure '7, in which position the valves 80 and 83 are closed, thus permitting fluid under pressure to be admitted to the upper tank 19, while still permitting normal operation of the lower tank 81. When the operating lever 311 is moved to dump position, that is, the dotted line position shown in Figure 8, the valve levers 3I5 and 342 are moved to the position shown in dotted lines in Figure 8. in which position the valve 8i] is closed but the valve 83 is open, the valves standing in these relations when the pressures in the tanks 19 and 8! have been equalized, so that material from the upper tank 19 may pass to the lower tank 8|.

During initial charging, it is preferable to close the valve 85 at the outlet of the tank 8|, movement of the valve 85 being effected by a chain 38! movable about a pulley 882, the chain being connected to a lever 385 connected to the plug of the valve 85. The chain preferably has its operating end positioned adjacent the operating arm 311.

Underlying the lower flange 334 of the lower tank 8! is an annular flange 352 having a central screw-threaded aperture receiving a tube portion between the flanges 334 and 352, and bolts 355 hold the flanges 334 and 352 in assembled relation. The valve 85 is interposed in a conduit 388 which has its upper end connected to the tube portion 353. The conduit 386 is reduced in diameter with respect to the tube portion 353, and the free end of the conduit 386 is provided with a pair of nipples 381. A control device 388 is positioned adjacent the tube portion 353, to indicate when a low level in the lower tank 81 has been reached, the device 388 comprising a pivoted vane 389 disposed within the tube portion 353, a shaft carrying the vane being rotatable with the vane and being adapted to actuate mercury switch means 390 disposed within a housing 39!. When the level in the lower tank 8! falls below the level of the vane shaft, the vane moves upwardly, thus causing desired actuation of the mercury switch 390.

In the embodiment shown (see Figure 7), one of the nipples 381 of the conduit 386 is closed by means of a cap closure 392, while the other nipple 381 has securely clamped thereto one end of the conduit 86. The conduit 88 comprises a heavy-duty flexible tube 383, within which is disposed a heavy-duty rubber hose 394, having its one end securely fastened over one nipple 381 and its other end extending into a "union joint suitably connected to the breech 81 of the gun 88.

In the simplest embodiment, the gun 88 serves to project the material at high velocity against an anvil, as fully described in application Serial Number 308,002, whereby the material'is disrupted by impact. To propel the material through the gun 88 air pressures as high as 500 pounds per square inch to the order of 1000 to 1500 pounds per square inch, or higher, may be utilized, this compressed air being supplied to the gun from the tank 8|. The gun 88 may include a booster jet, indicated in Figure 3 by the diagonal arrow against the diagrammatically indicated gun, and this jet may be connected to a conduit 434a (see Figure 3) which is tapped into the main air pressure conduit I89 ahead of the regulator I80, so that if desired air may be delivered to the jet under a pressure either higher or lower than that under which the air flows to the lower tank 81, thereby to permit adjustment to secude the optimum qualitative-quantitative output. A manually operated valve 436 is interposed in the conduit 434a to control the fiowof air to the jet and this valve is preferably closed and opened when the valve 85 at the outlet of the lower tank 8| is closed and opened. A regulator may be interposed in the conduit 434a. if desired.

The gun 88 may be of various embodiments, and more than one gun may be utilized, as fully described in application Serial Number 308,002.

As before mentioned, interlock means are provided, so constructed and arranged that certain parts of the apparatus are permitted to operate only when certain other parts are in a predetermined relation. Figure 13 shows an electrical diagram of the parts comprising the interlocking means and also parts comprising signaling means.

The devices shown in Figure 13, together with their relation to other parts by which they are controlled or which they control, are as follows. The switch housing 243 carried by and for movement with the operating lever 239 on the solids inlet valve 10, contains two mercury switches 625 and 626. Rotatable by the vane of the high level control 12 of the hoist tank are two mercury A suitab e gasket 854 is interposed switches 621 and 628, and rotatable by the vane ofthe low level control 13 of the hoist tank 1| are two mercury switches 629 and 630. Rotatable with the operatin lever of the three-way valve I62 which controls flow of air to or from the hoist tank 1| is a switch housing containing two mercury switches 63| and 632. The solenoid I12 cooperates with a core 634 connected to the valve "I in the blow-01f conduit I16, so that when the solenoid is energized the valve |1| is opened. Rotatable with the shaft 3|2 of the valve 60 is a casing 635 containing two mercury switches 636 and 631. The solenoid |6|, which operates the valve I66 in the air inlet conduit I56, cooperates with a core 666 connected to the valve I66 so that when the solenoid I6| is energized the valve I60 will be opened. Rotatable with the operating arm of the three-way valve I95 which controls flow of air to the upper tank 16 is a housing 640 containing a mercury switch 64L The housing 6| forming a part of the high level control of the receptacle 66 contains a mercury switch 645, and as before pointed out, the low levelcontrol 62 in receptacle 66 is mechanically connected to the high level control switch. The pressure responsive device 256, disposed within the hoist tank 1|, operates the switch 256 which comprises contacts 646 which are held in open position by the pressure responsive device 258 when a pressure above atmospheric pressure exists in the tank 1|, but are biased to closed position in any suitable manner when there is no pressure within the hoist tank 1|. A housing 656 is rotatable with the shaft 336 of the valve 63 and contains a mercury switch 65 I.

The devices shown in Figure 13 are connected to operate as follows. A master switch 655 controls the energization of main line wires 655 and 651, and all of the electrically operated parts of the apparatus receive electrical energy from these line wires. To start the apparatus, the master switch 655 is first closed. Assuming material is already in the new-materials container 56, a motor switch 658 is closed to cause energization of the motor 56 to start operation of the elevator 54. Simultaneously the light 51, in shunt with the motor 56, is energized, to indicate operation of the elevator 54. The circuit of the motor 56 and lamp 51 is from line wire 656, through switch 656, the armature of the motor 56 and the filament of the lamp 51 in parallel, through the closed contacts of the mercury switch 645 of the high level control 6|, through a conductor 666 connected to the other line Wire 651. Thus it will be obvious that the operation of the motor 56 is dependent upon the position of the switch 665 contained in the high level control 6|, the construction being such that when the level of material falls below the low level control 62, the switch 645 is operated to cause energization of the motor 56, and when the level of the material rises to the high level control 6|, the switch 645 is operate to interrupt the circuit of the motor 56.

The operation of the motor 61 of the elevator 63 is dependent upon the position of the high level control 12 on the hoist tank 1|, and on the position of the solids valve 16, which latter is in turn controlled by the pressure. responsive device 258, responsive to the presence or absence of a pressure within the hoist tank 1|. The connections are such that in order to effect operation of the elevator 63, the valve must have been opened (which requires zero pressure in the hoist tank 1|), and the level of the material within the hoist tank 1| must not be above the axis 256 of the operating vane 261 of the high level control 12. When these conditions exist, and a motor switch 662 is closed, the circuit of the motor 61 is from the main line wire 656, through the motor switch 662, the armature of the motor 61 and the filament of the lamp 68 in parallel, through a conductor 663, the then bridged terminals 625a of the mercury switch 625, a conductor 664, the then bridged terminals of the mercury switch 628 contained within the high level control 12, and a conductor 665, to the other main line wire 651. When the level of the material reaches the axis 256 of the high level control 12, the vane 251 of the high level control is moved to rotate the mercury switch 626, the mercury of the switch 628 moving away from the terminals of the switch and interrupts the circuit, thus stopping the elevator 66. At the same time the mercury in the switch 621 bridges the contacts of that switch thereby completing a circuit for a bell 666 or other signal, from the line 651, through a conductor 661 in which the switch 621 and bell are interposed, through the switch 662 to the other line 656. A switch 668 may be provided to manually interrupt the circuit of the signal 666.

The solids valve 16 is then closed, as by moving the operating lever 239 to its position shown in Figure 5, and the latching lever 246 is moved to latching relation with respect to the lever 239. This is possible because there is no pressure in the hoist tank 1| and hence the switch 259 is closed. The switch 256 completes a circuit for the solenoid 256, since the solenoid and the switch 259 are interposed in seriesin a conductor 683 the ends of which are connected to the line wires 656 and 651 respectively. Since the solenoid 250 is energized, the core 25| has been withdrawn from the path of the levers 238 and 246.

With the operating lever 236 of the solids inlet valve 16 in closed position, the casing 243 will be rotated, so that the mercury in the switch 625 bridges the terminals 625b and at the same time unbridges the terminals 625a. Unbridging of the terminals 625a prevents operation of the motor 61 when the solids valve 10 is closed. With material in the hoist tank 1| at a level a desired amount above the lower end of the tube 2|9, the vane 25'! of the low level control 13 will rotate the mercury switch 636, so that the mercury will bridge the terminals 636a. Then, if it is desired to hoist material, the operating lever 311 of the operating means 356 is moved to fill position, so that the valve 66 is open, while the valve 83 between the upper and lower tanks is closed, and the operating lever of the three-way valve I62 is moved manually to air input, hoist position, thus rotating the mercury switch 63I, so that the mercury will bridge the terminals of this switch. The opening movement of the valve causes the mercury in the switch 636 to bridge the terminals 636a. When all this has been done, the solenoid |6| will be energized, thus opening the valve I66, so that air may flow from the waste air tank I 49 to the hoist tank 1|. The circuit for the solenoid |6| is from the line wire 656, through the solenoid I 6|, a conductor 669, the contacts 666a, a conductor 610, the switch 63l, a conductor 61|, the contacts 636a, a conductor 612, the contacts 625b, and a conductor 613, to the line wire 651. It is of course clear that open position of any one of the switches in series with the solenoid |6| will prevent energizing of the solenoid, preventing air supply from the valve I 60 unless all is in readiness,

When enough material has been hoisted. from the hoist tank 1|, so that the level of the mate- :rial falls below 1 the axis 256 of the vane 251 of the low level device 13, the vane 251 will'ri'se, thus rotating'the switches 629 and 639, the mernow bridging the terminals of that switch.

Bridging ofthe terminals 63Gb lights a signal lamp 618, which may be of amber color, to indicate that a low level has been reached, the terminals 639!) and the, lamp 618 being .interposed in series in conductor 680, connected at its ends to the line wires 656 and 651. The interruption of terminals 630a, interrupts the previously traced circuit of the solenoid I6I, thereby causing closure of the air inlet valve I66. At the same time, bridging of the terminals of the switch 629 causes energization of the solenoid 112, thereby causing opening of the blow-off valve I1 I. The solenoid I12 is energized from the line wire 656, a conductor GBI in which the solenoid is interposed, a conductor 682, through the terminals of switch 629, through conductor 689, to the line wire 651. Closing of the inlet valve I60 and opening of the blow-off valve I1I of course relieves the pressure in the hoist tank H and hoisting of material ceases.

Material having been hoisted into the upper feed tank 19 from the hoist tank 1|, the operating lever 311 of the operating means 356 is then moved along the quadrant 314 from fill position to compress position, thus causing closure of the valve 89 at theinlet of the upper .tank 19. lower tanks remains closed. With the valve 83 The valve 83 between the upper and 80 causes rotation of the switch casing 635, and

effects shifting of the mercury switches 636 and 631, so that the. mercury. within the switch 636 unbridges the terminals 636a and bridges the terminals 636b, and the mercury in the switch 631 bridges the terminals of that switch. Bridging of the terminals 636b completesv a circuit for the solenoid I12, from line wire 651, through a conductor 686 in which the terminals 6361) are interposed, to the conductor 69 I, through the solenoid I12, to the line wire 656. This insures that the blow-off valve I1I will be open when the valve 86 is closed, so that even if air under pressure seeped into the hoist tank II, it could not set up pressure that could cause hoisting of material at this time, which would be undesirable, because the valve 86 is closed, and hoisted .material would -be blown into the bag 283. The control-lever of the valve I95 is now moved to .compress position, such movement causing rotation of the switch casing 649 movable with the operating lever of the valve, in such direction that the mercury is moved from bridging relation with respect .to the terminals of the switch 64I, thereby insuring deenergization of the solenoid 319 so that the core 389 prevents movement of the lever 311 to the dump position at this time. v

After-the pressure in the upper tank 19 has been raised toor substantially near the'pressure in the lower tank 8i, the operating lever of the switch.

18 the valve I95 is moved from compress position to equalize position, such movement causing rotation of the casing 649, so that the mercury bridges the terminals of the mercury switch 6M, and causes energization of the solenoid 319, thereby withdrawing the core 369 from the path of movement of the indicating portion 316 of the operating lever 311, The solenoid 319 is so energized since it and the switches 6M and 631 are connected in series in a conductor 691 the ends of which are connected to the line wires 656 and; 651, it being remembered that theswitch 631 was previously closed by closure of the valve 99. The operating lever 311 may now be moved to dump position, whereupon the valve 60 at the inlet of the upper feed tank 19 remains closed, and the valve 63 between the upper and lower tanks is opened, such movement of the valve 63 causing movement of the casing 659, so that the mercury in the switch 65! bridges the terminals 65lb, thereby causing energization of a red light 688, which is interposed in series with the terminals 65) in a conductor 689 the ends of which are connected to the line wires 655 and 651. The red light 688 indicates that material is being dumped. The green lamp 685 is out, by reason of opening of terminals 65Ia, if the valve 83 is open or is not tightly closed, and the red lamp 688 is lit when the valve 93 is open or not tightly closed.

After the material ha been dumped from the upper feed tank 19 to the lower tank 9|, the operating lever 311 of the operating means 356 is moved along the quadrant to blow-oil position, in which position the valves 89 and 83 are still closed, and the operating lever of the valve I95 is moved from equalize position to dead position, the latter action immediately causing deenergization of the solenoid 319, so

that the core 389 is moved by the spring 389a to the position wherein it prevents the operating lever 311 from being moved to dump position. The movement of the operating lever of the valve I95 to dead position efiects de'energization of the solenoid 319, since in that position the mercury in the switch 64! is moved from bridging relation with respect to the terminals of The valve 85 at the outlet of the lower tank 8| is then opened to permit the fluid under pressure in the lower tank to convey the material within the lower tank to the gun breach 81 and gun 8B.

To give a signal before the material is completely exhausted from the lower tank ill, the

switch 388 is so arranged in the outlet conduit of this lower tank that when the material falls .below the pivot of the vane 389, the vane may be spring pressed or otherwise moved to a substantially horizontal position, so as to energize a red light 699, and to cause ringing of a bell 69!, the circuit for the lamp 699 being from the line wire 656, the conductor 686, a conductor 693, through the lamp 696 and the switch 390, to the conductor 666, to the line wire 651, and the bell 69I' being connected in shunt with the lamp 695], and if desired, controllable by a further switch 694.

' To relieve the upper tank of pressure, so that this tank may be in condition to receive another charge of material from the hoist tank H, the operator moves the operating lever of the valve I15 to the position indicated by the letter a,thus permitting flow of air along the conduit I19, through the body of the valve I15, through the conduit I52, to the waste air tank M9, until the "safety Valves I56 indicate that the tank I49 has received its full charge, at which point the operator moves the operating lever of the valve I 15 to the position indicated by the letter b, to permit sition, thus opening the valve 86, so that the upper tank 19 is in condition to receive another charge 1 of material.

v Assuming that the valve -I62'isin the dead position, that the solids valve 16 is open, and that the low-level control 13 is in the position corresponding to low level of material in the hoist-tank, the terminals of the switch 632 associated with the valve I62 will be bridged, and the terminals 0f the switch 626 associated with'the solids valve 10 will also be bridged. This completes a circuit for the solenoid I12 from the line wire'651, the conductor 695 in which the switches 626 and 632 are interposed in series, to the conductor 632, to

the conductor 68I, through the solenoid I12, to the line wire 656. Therev is also a circuit for the solenoid I12 from the line wire 651, the conductor 680, the conductor 682 in which the switch 629 is interposed, the conductor 68L through. the

solenoid I12, to the line wire 656. Assuming that the elevator motor 61 is set in operation, as hereinbefore described, and the level of material rises in the hoist tank 1|, when the level rises enough to cause the low level control 13 to respond, the switch 629 opens, but the solenoid I12 remains ized as long as the switches 626 and 632 are closed, and even after the switches 626 and 632 are opened, the solenoid I12 still will remain energized, if the valve 86 is in such position that the terminals 6361) of the switch 636 are bridged.

Besides the automatic control of the solenoid I12 for the purpose of opening the blow-off valve I1I, to relieve pressure in the hoist tank H, the

pressure may be relieved manually b moving the control lever of the valve I62 into the blow-off position, whereby the air may flow out through conduits 14 and I64, through the valve I62, to the conduit I66, to the conduit I13, and thence to atmosphere, at the mufiler I69.

The valve 35 is closed when initially charging the apparatus, and may also be closed for inter- .rupting the process temporarily without relieved pressure on the lower feed tank 8|, or at the end of a run prior to a subsequent initial charging or beginning of operations. In other Words, it is closed before initially charging, or at the end of a days run, or for temporary interruption, and it is opened when beginning operations, as at the beginning of a day, or after an interruption as for inspection or adjustment of other equipment.

While the material in the lower-feed tank8l is being ground, the hoist tank 1| will have again been filled, with either new material or with a:

mixture of new and partly ground material from overage from the screen 96, and this" charge will have been hoisted, and all is in readiness to dump the same into'the tank 8I' when the -low level responsive device in the lower tank BI indicates sufficient evacuation to receive the next charge'from the upper feed tank16.

, From the foregoing description of the apparatus and-the operation thereof; it will 'be apparent that Operation of the apparatus and'proces's 'affe a predetermined-level to reducethe flu the other hand, it also will be obvious to'those skilled in the art that the illustrated embodiment of my invention may be variously changed and modified, and features thereof, singly or collectively,'embodied in combinations other than those illustrated;withoutideparting from the spirit'of my invention or sacrificing the advantages thereof, and'a'ccordingly, that'the disclosure herein is illustrative only,"and that my invention isnotlimited thereto. I

I claim:

1. Means for conveying material bymeans of fluid under pressure, comprising: a tank having an inlet through which material may be received and an outlet through which material maybe discharged; valve" means controlling said material inlet; means adapted to locksaid material inlet valve means in closed position'; operating means, for operating'said material inlet valve means, so constructed and arranged that it is operable to open said valve means "only when said locking means iscaused to release said material inlet valve means; means for introducing fluid under pressure into said tank; said tank having an outlet through which fluid under pressure may be discharged; valve means controlling said pressure outlet; means, responsive to the level of material in said tank, so constructed and arranged that said pressure outlet valve means is actuated to open position to reduce the fluid pressure in said tank to atmospheric pressure when the level of material in said'tank is below a"predetermined level; means responsive to the fluid pressure in said tank; ahd means, controlling said locking means -in response to said pressureres ponsive means, so constructed and arranged that said locking means releasessaid material inlet valve means upon reduction in said fluid pressure to atmospheric pressure. 2. Means for conveying material by means of fluid under pressure, comprising: a tank having an inlet through which material may be received and an outletthrough which material may be discharged; valve means controlling said 'material inlet; means adapted to lock said material inlet valve means in closed position; operating arranged that said pressure outletf-valvemeans is actuated to open'p'osition' and' said pressure inlet valve means isactuatd to' closed position when the level of material insaid tank-is below L s pressure in said tank to atmospheric pressure; "ea sresponsive to'the' fluidprs'sure'irisaid ank, -and fineans, controlling *said l'ocking means iii-response to said pressure res onsive' meafisso"'cbnstruet- 21 ed and arranged said material inlet valve means upon reduction in said fluid pressure to atmospheric pressure.

3. In combination: a tank having an inlet through which material may be received and an outlet through which material may be discharged; first valve means controlling said inlet; means for connecting said tank to a source of fluid under pressure; separately operable second valve means interposed in said connecting means; said tank having a pressure outlet through which fluid under pressure may be discharged from said tank; third valve means, controlling said pressure outlet; and control means for said third valve means, including means responsive to the position of said first valve means and means responsive to the position of said second valve means, constructed and arranged to cause opening of said third valve means when said first valve means is open and said second valve means is closed.

4. Means for conveying material by means of fluid under pressure, comprising: a tank having a first inlet through which fluid under pressure may be admitted, and also having a second inlet through which material may be received; first valve means controlling said first inlet; means for operating said first valve means to open position; second valve means controlling said second inlet; third valve means in series with said first valve means; means for separately operating said second valve means and said third valve means; means, responsive to the position of said third valve means, so constructed and arranged that actuation of said third valve means to open position renders possible operation of said operating means for said first valve means; and means, responsive to the position of said second valve means, so constructed and arranged that operation of said operating means for said first valve means is prevented if said second valve means is in open position.

5. Means for conveying material by means of fluid under pressure, comprising: a tank having a first inlet through which fluid under pressure may be admitted, and also having a second inlet through which material may be received; first valve means controlling said first inlet; means for operating said first valve means to open position; second valve means controlling said second inlet; third valve means in series with said first valve means; means for separately operating said second valve means and said third valve means; said tank having a pressure outlet through which fluid under pressure may be discharged from said tank; fourth valve means, controlling said pressure outlet; means, responsive to the position of said third valve means, so constructed and arranged that actuation of said third valve means to open position renders possible operation of said operating means for said first valve means; means, responsive to the position of said second valve means, so constructed and arranged that operation of said operating means for said first that said locking means releases 6 valve means is prevented if said second valve means is in open position; and control means for said fourth valve means, including means responsive to the position of said second valve means and means responsive to the position of said third valve means, constructed and arranged to cause opening of said fourth valve means when said second valve means is open and said third valve means is closed.

6. Means for conveying material by means of fluid under pressure, comprising: a tank having a first inlet through which fluid under pressure may be admitted, and also having a second inlet through which material may be received, and also having a pressure outlet through which fluid under pressure may be discharged from said tank; first valve means controlling said first in let; second valve means controlling said second inlet; third valve means for controlling said pressure outlet; means for separately operating said second valve means and said first valve means; and control means, responsive to the position of said second valve means, including means for controlling said first valve means, and including means for controlling said third valve means, so constructed and arranged that when said third valve means has been opened, said second valve means, when in open position, maintains said third valve means open, and said second valve means, when in open position, prevents opening of said first valve means.

'7. Means for conveying material by means of fluid under pressure, comprising: a tank having a first inlet through which fluid under pressure may be admitted, and also having a second inlet through which material may be received, and also having a pressure outlet through which fluid under pressure may be discharged jrom said tank; first valve means controlling said first inlet; second valve means controlling said second inlet; third valve means for controlling said pressure outlet; means for feeding material to said tank through said second valve means; means for separately operating said second valve means and said first valve means; and control means, responsive to the position of said second valve means, including means for controlling said material feeding means, so constructed and arranged that the operation of said feeding means is made possible only when said second valve means is open, and including means for controlling said first valve means, so constructed and arranged that the opening of said first valve means is made possible only when said second valve means is closed, and including means for controlling said third valve means, so constructed and arranged that when said third valve means has been opened, said second valve means, when in open position, maintains said third valve means open, and said second valve means, when in open position, prevents opening of said first valve means.

EDWIN L. WIEGAND.

Certificate of Correction Patent No. 2,413,479. December 31, 1946. EDWIN L. WIEGAND It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 9, line 6, for single read signal; column 14, line 47, for secude read secure; and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Ofioe.

Signed and sealed this 4th day of March, A. D. 1947.

LESLIE FRAZER,

First Assistant Oommissz'oner of Patents. 

